[SCSI] iscsi_tcp, libiscsi: initial AHS Support
at libiscsi generic code
- currently code assumes a storage space of pdu header is allocated
at llds ctask and is pointed to by iscsi_cmd_task->hdr. Here I add
a hdr_max field pertaining to that storage, and an hdr_len that
accumulates the current use of the pdu-header.
- Add an iscsi_next_hdr() inline which returns the next free space
to write new Header at. Also iscsi_next_hdr() is used to retrieve
the address at which to write the header-digest.
- Add iscsi_add_hdr(length). What the user do is calls iscsi_next_hdr()
for address of the new header, than calls iscsi_add_hdr(length) with
the size of the new header. iscsi_add_hdr() will check if space is
available and update to the new size. length must be padded according
to standard.
- Add 2 padding inline helpers thanks to Olaf. Current patch does not
use them but Following patches will.
Also moved definition of ISCSI_PAD_LEN to iscsi_proto.h which had
PAD_WORD_LEN that was never used anywhere.
- Let iscsi_prep_scsi_cmd_pdu() signal an Error return since now it is
possible that it will fail.
- I was tired of yet again writing a "this is a digest" comment next to
sizeof(__u32) so I defined a new ISCSI_DIGEST_SIZE. Now I don't need
any comments. Changed all places that used sizeof(__u32) or "4" in
connection to a digest.
iscsi_tcp specific code
- At struct iscsi_tcp_cmd_task allocate maximum space allowed in
standard for all headers following the iscsi_cmd header. and mark
it so in iscsi_tcp_session_create()
- At iscsi_send_cmd_hdr() retrieve the correct headers size and
write header digest at iscsi_next_hdr().
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Olaf Kirch <olaf.kirch@oracle.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index fd88777..491845f 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -113,7 +113,7 @@
struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
crypto_hash_digest(&tcp_conn->tx_hash, &buf->sg, buf->sg.length, crc);
- buf->sg.length += sizeof(u32);
+ buf->sg.length += ISCSI_DIGEST_SIZE;
}
/*
@@ -220,6 +220,7 @@
iscsi_tcp_chunk_done(struct iscsi_chunk *chunk)
{
static unsigned char padbuf[ISCSI_PAD_LEN];
+ unsigned int pad;
if (chunk->copied < chunk->size) {
iscsi_tcp_chunk_map(chunk);
@@ -243,10 +244,8 @@
}
/* Do we need to handle padding? */
- if (chunk->total_copied & (ISCSI_PAD_LEN-1)) {
- unsigned int pad;
-
- pad = ISCSI_PAD_LEN - (chunk->total_copied & (ISCSI_PAD_LEN-1));
+ pad = iscsi_padding(chunk->total_copied);
+ if (pad != 0) {
debug_tcp("consume %d pad bytes\n", pad);
chunk->total_size += pad;
chunk->size = pad;
@@ -1385,11 +1384,11 @@
}
iscsi_buf_init_iov(&tcp_ctask->headbuf, (char*)ctask->hdr,
- sizeof(struct iscsi_hdr));
+ ctask->hdr_len);
if (conn->hdrdgst_en)
iscsi_hdr_digest(conn, &tcp_ctask->headbuf,
- (u8*)tcp_ctask->hdrext);
+ iscsi_next_hdr(ctask));
tcp_ctask->xmstate &= ~XMSTATE_CMD_HDR_INIT;
tcp_ctask->xmstate |= XMSTATE_CMD_HDR_XMIT;
}
@@ -2176,7 +2175,8 @@
struct iscsi_cmd_task *ctask = session->cmds[cmd_i];
struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
- ctask->hdr = &tcp_ctask->hdr;
+ ctask->hdr = &tcp_ctask->hdr.cmd_hdr;
+ ctask->hdr_max = sizeof(tcp_ctask->hdr) - ISCSI_DIGEST_SIZE;
}
for (cmd_i = 0; cmd_i < session->mgmtpool_max; cmd_i++) {
diff --git a/drivers/scsi/iscsi_tcp.h b/drivers/scsi/iscsi_tcp.h
index f1c5411..eb3784f 100644
--- a/drivers/scsi/iscsi_tcp.h
+++ b/drivers/scsi/iscsi_tcp.h
@@ -41,7 +41,6 @@
#define XMSTATE_IMM_HDR_INIT 0x1000
#define XMSTATE_SOL_HDR_INIT 0x2000
-#define ISCSI_PAD_LEN 4
#define ISCSI_SG_TABLESIZE SG_ALL
#define ISCSI_TCP_MAX_CMD_LEN 16
@@ -130,14 +129,14 @@
struct iscsi_data_task {
struct iscsi_data hdr; /* PDU */
- char hdrext[sizeof(__u32)]; /* Header-Digest */
+ char hdrext[ISCSI_DIGEST_SIZE];/* Header-Digest */
struct iscsi_buf digestbuf; /* digest buffer */
uint32_t digest; /* data digest */
};
struct iscsi_tcp_mgmt_task {
struct iscsi_hdr hdr;
- char hdrext[sizeof(__u32)]; /* Header-Digest */
+ char hdrext[ISCSI_DIGEST_SIZE]; /* Header-Digest */
int xmstate; /* mgmt xmit progress */
struct iscsi_buf headbuf; /* header buffer */
struct iscsi_buf sendbuf; /* in progress buffer */
@@ -159,9 +158,11 @@
};
struct iscsi_tcp_cmd_task {
- struct iscsi_cmd hdr;
- char hdrext[4*sizeof(__u16)+ /* AHS */
- sizeof(__u32)]; /* HeaderDigest */
+ struct iscsi_hdr_buff {
+ struct iscsi_cmd cmd_hdr;
+ char hdrextbuf[ISCSI_MAX_AHS_SIZE +
+ ISCSI_DIGEST_SIZE];
+ } hdr;
char pad[ISCSI_PAD_LEN];
int pad_count; /* padded bytes */
struct iscsi_buf headbuf; /* header buf (xmit) */
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 0beb4c6..0d7914f 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -37,6 +37,9 @@
#include <scsi/scsi_transport_iscsi.h>
#include <scsi/libiscsi.h>
+static void fail_command(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
+ int err);
+
struct iscsi_session *
class_to_transport_session(struct iscsi_cls_session *cls_session)
{
@@ -122,6 +125,20 @@
}
EXPORT_SYMBOL_GPL(iscsi_prep_unsolicit_data_pdu);
+static int iscsi_add_hdr(struct iscsi_cmd_task *ctask, unsigned len)
+{
+ unsigned exp_len = ctask->hdr_len + len;
+
+ if (exp_len > ctask->hdr_max) {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+
+ WARN_ON(len & (ISCSI_PAD_LEN - 1)); /* caller must pad the AHS */
+ ctask->hdr_len = exp_len;
+ return 0;
+}
+
/**
* iscsi_prep_scsi_cmd_pdu - prep iscsi scsi cmd pdu
* @ctask: iscsi cmd task
@@ -129,13 +146,19 @@
* Prep basic iSCSI PDU fields for a scsi cmd pdu. The LLD should set
* fields like dlength or final based on how much data it sends
*/
-static void iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
+static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
{
struct iscsi_conn *conn = ctask->conn;
struct iscsi_session *session = conn->session;
struct iscsi_cmd *hdr = ctask->hdr;
struct scsi_cmnd *sc = ctask->sc;
+ unsigned hdrlength;
+ int rc;
+ ctask->hdr_len = 0;
+ rc = iscsi_add_hdr(ctask, sizeof(*hdr));
+ if (rc)
+ return rc;
hdr->opcode = ISCSI_OP_SCSI_CMD;
hdr->flags = ISCSI_ATTR_SIMPLE;
int_to_scsilun(sc->device->lun, (struct scsi_lun *)hdr->lun);
@@ -199,6 +222,15 @@
hdr->flags |= ISCSI_FLAG_CMD_READ;
}
+ /* calculate size of additional header segments (AHSs) */
+ hdrlength = ctask->hdr_len - sizeof(*hdr);
+
+ WARN_ON(hdrlength & (ISCSI_PAD_LEN-1));
+ hdrlength /= ISCSI_PAD_LEN;
+
+ WARN_ON(hdrlength >= 256);
+ hdr->hlength = hdrlength & 0xFF;
+
conn->scsicmd_pdus_cnt++;
debug_scsi("iscsi prep [%s cid %d sc %p cdb 0x%x itt 0x%x len %d "
@@ -206,6 +238,7 @@
sc->sc_data_direction == DMA_TO_DEVICE ? "write" : "read",
conn->id, sc, sc->cmnd[0], ctask->itt, scsi_bufflen(sc),
session->cmdsn, session->max_cmdsn - session->exp_cmdsn + 1);
+ return 0;
}
/**
@@ -744,7 +777,10 @@
conn->ctask = list_entry(conn->xmitqueue.next,
struct iscsi_cmd_task, running);
- iscsi_prep_scsi_cmd_pdu(conn->ctask);
+ if (iscsi_prep_scsi_cmd_pdu(conn->ctask)) {
+ fail_command(conn, conn->ctask, DID_ABORT << 16);
+ continue;
+ }
conn->session->tt->init_cmd_task(conn->ctask);
conn->ctask->state = ISCSI_TASK_RUNNING;
list_move_tail(conn->xmitqueue.next, &conn->run_list);
@@ -1534,6 +1570,7 @@
if (cmd_task_size)
ctask->dd_data = &ctask[1];
ctask->itt = cmd_i;
+ ctask->hdr_max = sizeof(struct iscsi_cmd);
INIT_LIST_HEAD(&ctask->running);
}
diff --git a/include/scsi/iscsi_proto.h b/include/scsi/iscsi_proto.h
index 751c81e..6947082 100644
--- a/include/scsi/iscsi_proto.h
+++ b/include/scsi/iscsi_proto.h
@@ -27,7 +27,7 @@
#define ISCSI_LISTEN_PORT 3260
/* Padding word length */
-#define PAD_WORD_LEN 4
+#define ISCSI_PAD_LEN 4
/*
* useful common(control and data pathes) macro
@@ -147,6 +147,14 @@
__be32 read_length;
};
+/* Extended CDB AHS */
+struct iscsi_ecdb_ahdr {
+ __be16 ahslength; /* CDB length - 15, including reserved byte */
+ uint8_t ahstype;
+ uint8_t reserved;
+ uint8_t ecdb[260 - 16]; /* 4-byte aligned extended CDB spillover */
+};
+
/* SCSI Response Header */
struct iscsi_cmd_rsp {
uint8_t opcode;
diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index e1fb3d0..a9a9e86 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -78,6 +78,9 @@
#define ISCSI_ADDRESS_BUF_LEN 64
enum {
+ /* this is the maximum possible storage for AHSs */
+ ISCSI_MAX_AHS_SIZE = sizeof(struct iscsi_ecdb_ahdr) +
+ sizeof(struct iscsi_rlength_ahdr),
ISCSI_DIGEST_SIZE = sizeof(__u32),
};
@@ -102,10 +105,13 @@
struct iscsi_cmd_task {
/*
- * Becuae LLDs allocate their hdr differently, this is a pointer to
- * that storage. It must be setup at session creation time.
+ * Because LLDs allocate their hdr differently, this is a pointer
+ * and length to that storage. It must be setup at session
+ * creation time.
*/
struct iscsi_cmd *hdr;
+ unsigned short hdr_max;
+ unsigned short hdr_len; /* accumulated size of hdr used */
int itt; /* this ITT */
uint32_t unsol_datasn;
@@ -124,6 +130,11 @@
void *dd_data; /* driver/transport data */
};
+static inline void* iscsi_next_hdr(struct iscsi_cmd_task *ctask)
+{
+ return (void*)ctask->hdr + ctask->hdr_len;
+}
+
struct iscsi_conn {
struct iscsi_cls_conn *cls_conn; /* ptr to class connection */
void *dd_data; /* iscsi_transport data */
@@ -342,4 +353,22 @@
extern void iscsi_pool_free(struct iscsi_queue *, void **);
extern int iscsi_pool_init(struct iscsi_queue *, int, void ***, int);
+/*
+ * inline functions to deal with padding.
+ */
+static inline unsigned int
+iscsi_padded(unsigned int len)
+{
+ return (len + ISCSI_PAD_LEN - 1) & ~(ISCSI_PAD_LEN - 1);
+}
+
+static inline unsigned int
+iscsi_padding(unsigned int len)
+{
+ len &= (ISCSI_PAD_LEN - 1);
+ if (len)
+ len = ISCSI_PAD_LEN - len;
+ return len;
+}
+
#endif
